In general, mobile communication systems have been developed to provide communication while securing mobility of users. Thanks to rapid technical advances, mobile communication systems have reached the stage of providing high-speed data communication services as well as voice communication services. In recent years, evolved studies on long term evolution-advanced (LTE-A) are underway in 3GPP as one of the next generation mobile communication systems. LTE-A has been almost completed in late 2010 for commercialization, and technologies with higher data rates than currently available rates have been discussed.
With completion of the LTE specification, recently, active discussions are in progress on evolved LTE systems (LTE-Advanced, LTE-A) to further improve the transmission speed by combining various new technologies with the LTE communication system. Hereinafter, the LTE system will be understood to include the existing LTE system and the LTE-A system.
In the LTE-A system, the base station may configure a primary cell (PCell) and a secondary cell (SCell) for a user equipment and provide a service to the user equipment through at least two cells. This can provide a higher traffic rate to the user equipment or user. However, even if the traffic of the user equipment is below a given level, configuring an SCell to the user equipment may waste resources. Hence, a method for dynamically operating the SCell is required.